The present invention relates to a tissue stimulator system of the pacemaker type, and more particularly to an improved connection system for coupling a catheter to such a pulse generator.
As is well known, body-implantable electronic pacers have been developed for artificially stimulating an organ, such as a heart, to correct or modify its behavior. In the case of the heart, stimulation is accomplished by transmitting electrical impulses from an implanted cardiac pacer to an electrode disposed in an appropriate area of heart muscle tissue by means of a catheter.
Several different types of cardiac pacers have been developed, and different sorts of electrical impulses provided by the pacers in order to more appropriately respond to cardiac malfunctions. Generally speaking, most pacers are implantable and comprise a small, self-contained sealed unit including a source of electrical energy and an electronic device for producing impulses at appropriate intervals. After a preliminary check of a pacer, it is implanted by surgically creating a subcutaneous cavity into which the pacer is slipped. An electrode at one end of a catheter is surgically implanted in cardiac tissue. The other end of the catheter is extended to the pacer, and connected to it in order to complete the necessary electrical circuit.
The conventional manner of electrically coupling the catheter to the pacer is comparatively elaborate. The pacer is provided with a female conductive member having an elongate passage for receiving a male connector of the catheter. A tapped hole extends through the side of the member to the passage. In order to electrically couple the catheter and the pacer, the male catheter connector is slipped into the passage, the fit being relatively loose. A set screw is then screwed into the threaded passage by means of a small wrench, and tightly urged against the side of the catheter connector. A sealing screw, and often an "O" ring, are then introduced into the threaded hole to prevent the set screw from loosening. Often surgical cement or sealing compound is then used to secure the sealing screw. Finally, a rubber boot which is attached to the pacemaker body and surrounds the entrance of the female connector is sealed around the male catheter connector tip by tying the boot with a length of non-absorbable suture.
The type of connector thus described, and the rather elaborate procedures necessary to connect and seal the catheter to the pacer, are required both to assure good electrical contact and to seal the connector against the ingress of body fluids. While the above-described procedure and apparatus have been widely and successfully used, in practice a number of disadvantages are inherent in them. The manipulation of the extremely small screws, seals and the like which are required is time-consuming and taxing, and difficulties may be presented in correctly manipulating and assembling a number of loose parts in the manner described. Further, when round male and female connectors are used, as is commonly the case, only line contact is achieved between the elements. Finally, removal of the pacer is complicated by the need for removal of sealing compound, sealing screws, and set screws. Accordingly, it will be understood that it would be highly advantageous to provide an implantable pacer with an improved connection means which obviates some or all of the foregoing problems.
It is therefore an object of the present invention to provide an implantable pacer having an improved connector.
Another object is to provide a pacer with a frictionally-engaging contact system.
Yet another object is to eliminate the need for separable locking means in a pacer connector.
A further object of the invention is to provide an improved connector for use with an implantable electronic pacer.